The present invention relates generally to cooling techniques, and more specifically to a liquid cooling system for LSI (large scale integration) packages.
In a prior art liquid cooling system, a plurality of LSI (large scale integration) packages are mounted on a printed circuit board and a plurality of heat sinks are secured respectively on the LSI packages in a heat transfer contact therewith. A housing is sealed against the printed circuit board to define a cooling chamber, which is filled with liquid coolant so that the LSI packages and heat sinks are submerged in the liquid. Local boiling of the liquid occurs at heated areas of the heat sinks, causing columns of bubbles to rise. However, because of the difficulty to precisely maintain the coolant in a condition that causes vaporization to occur in a nucleate boiling state, a film tends to develop in the liquid over the heat sinks. This is what is called "film boiling" which severely limits the efficiency of the cooling operation.